package com.boot;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;

import java.util.Arrays;

@SpringBootApplication
public class FirstProgramApplication {

    public static void main(String[] args) {
        SpringApplication.run(FirstProgramApplication.class, args);
    }


    // 下面的代码，在项目启动时，会执行，
    // 打印启动时加载的bean
    @Bean
    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
        // 下面使用的是lambda表达式,编译器根据方法体推测，返回一个CommandLineRunner对象
        return args -> {
            System.out.println("Let's inspect the beans provided by Spring Boot:");
            String[] beanNames = ctx.getBeanDefinitionNames();
            Arrays.sort(beanNames);
            for (String beanName : beanNames) {
                System.out.println(beanName);
            }
        };
    }


}
